Greatly enhanced tribocatalytic purification of concentrated dye wastewater by TiO2 nanoparticles through Ti and Al2O3 coatings

TiO 2 nanoparticles with high chemical stability, low cost and non-toxicity are attractive for large-scale catalytic applications. Non-piezoelectric amorphous TiO 2 nanoparticles were experimentally developed for the efficient degradation of dyes under mechanical friction induced by low-speed stirring at 400 rpm. The friction between the catalyst surface and the rotating disk promotes the transition of valence-band electrons in TiO 2 , generating electron-hole pairs. These pairs subsequently react with hydroxide ions and dissolved oxygen in the dye solution to produce superoxide radicals and hydroxyl radicals, enabling the degradation of organic dyes under tribo-catalytic conditions. Al 2 O 3 substrates were optimized compared to glass substrates. Non-piezoelectric amorphous TiO 2 nanoparticles were mechanically stirred at 400 rpm for 2 h and 2.5 h. Under these conditions, high-concentration methyl orange (30 mg/L) and methylene blue (20 mg/L) degraded by 99 % and 100 %, respectively. The tribocatalytic performance achieved for TiO 2 nanoparticles in this study is highly competitive for environmental remediation. The schematic diagram of UV–Vis characterization of the degradation and purification of high-concentration MO (30 mg/L) and MB (20 mg/L) by anatase-structured TiO 2 combined with Al 2 O 3 substrate demonstrates outstanding performance in purifying and degrading high-concentration dye wastewater. • Non-piezoelectric amorphous TiO 2 is employed for the friction-catalytic degradation of dye-containing wastewater. • Compared with glass and Ti substrates, the Al 2 O 3 substrate demonstrates superior friction catalytic performance. • The MO dye wastewater (30 mg/L) is effectively degraded within 2 h in the Al 2 O 3 substrate. • The MB dye wastewater(20 mg/L) is effectively decomposed within 2.5 h in the Al 2 O 3 substrate. • Non-piezoelectric amorphous TiO 2 nanopowders maintain excellent cycle performance and structural stability during the friction catalysis process. • The electron transfer mechanism involving energy transfer effectively supports the elucidation of the frictional catalysis mechanism.